https://chromium-review.googlesource.com/c/596511 fixes the first problem. After that:

ninja -t msvc -e environment.x64 -- C:\goma\goma-win64/gomacc.exe "d:\src\chromium\src\third_party\depot_tools\win_toolchain\vs_files\f53e4598951162bad6330f7a167486c7ae5db1e5\vc\bin\amd64/cl.exe" /nologo /showIncludes  @obj/media/midi/midi/midi_manager_win.obj.rsp /c ../../media/midi/midi_manager_win.cc /Foobj/media/midi/midi/midi_manager_win.obj /Fd"obj/media/midi/midi_cc.pdb"
../..\base/bind_internal.h(196): error C2220: warning treated as error - no 'object' file generated
../..\base/bind_internal.h(266): note: see reference to function template instantiation 'R base::internal::FunctorTraits<void (__cdecl midi::MidiManager::* )(uint32_t,midi::mojom::PortState),void>::Invoke<_Ty,const size_t&,const midi::mojom::PortState&>(R (__cdecl midi::MidiManager::* )(uint32_t,midi::mojom::PortState),ReceiverPtr &&,const size_t &,const midi::mojom::PortState &)' being compiled
       with
       [
           R=void,
           _Ty=midi::MidiManagerWin *,
           ReceiverPtr=midi::MidiManagerWin *
       ]

crrev.com/c/596348 will fix that one.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/aeed1e4da5431f08168293a3d69369710319309b

commit aeed1e4da5431f08168293a3d69369710319309b
Author: Justin Schuh <jschuh@chromium.org>
Date: Tue Aug 01 19:46:43 2017

Fix MSVC release build after r490852

Disable integer overflow warnings in integer overflow tests.

TBR=thakis@chromium.org

Bug:  751198 
Change-Id: Ia5680199a51f0ecb951744838e624f9d6f1d7573
Reviewed-on: https://chromium-review.googlesource.com/596511
Reviewed-by: Justin Schuh <jschuh@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Justin Schuh <jschuh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491085}
[modify] https://crrev.com/aeed1e4da5431f08168293a3d69369710319309b/base/safe_numerics_unittest.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3d4cdf6a2b304b8a04efe2fd9331ee9518ad6f17

commit 3d4cdf6a2b304b8a04efe2fd9331ee9518ad6f17
Author: Nico Weber <thakis@chromium.org>
Date: Tue Aug 01 21:41:56 2017

Let win_clang trybot and WinClang64 (dbg) main waterfall bot do release builds.

We most care about having release MSVC builds working, so make that the
configuration we test on the main waterfall.

Bug:  751198 
Change-Id: I3d939b50351bd3112a9b079a87087e2a729394f8
Reviewed-on: https://chromium-review.googlesource.com/596747
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491120}
[modify] https://crrev.com/3d4cdf6a2b304b8a04efe2fd9331ee9518ad6f17/tools/mb/mb_config.pyl